4-Chloropyridine → 8-(Pyridin-4-yl)-1,4-dioxa-8-azaspiro[4.5]decane

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Reaction Steps

A solution of 46 g (0.4 mol) 4-chloropyridine and 123.5 g (0.86 mol) 4-piperidone ethylene ketal is heated for 48 hours to reflux in 400 ml p-xylene. Subsequently the reaction mixture is cooled, the precipitated precipitate is removed by filtration, the mother liquor is concentrated to dryness and the residue is purified by column chromatography on silica gel (ethyl acetate/saturated ammonia-alkaline methanol 9/1). In this way 79.7 g (90%) 8-pyridin-4-yl-1,4-dioxa-8-aza-spiro[4.5]decane is obtained as a white powder. m/e=220; f.p.=65° C.

Provenance & Evidence